Migrating birds arrive in the autumn and leave in spring. Where do they come from? Where are they heading to? Would they be coming again next year? Throughout time, this has been a riddle for people with an interest in science or just the romance of nature. Legend has it that 2,000 years ago, a palace consort in the kingdom of Wu tied a red string onto the leg of the swallow to find out whether the same bird would return the following year to its nest above her window.
Napahai is a wetland paradise in Shangri-la of southwest China, bordering the Tibetan plateau. The pristine state of this ecosystem provides an ideal wintering home for the Black-necked Cranes. Every year as weather on the high plateau turns bitterly cold, over 300 Black-necked Cranes migrate from the north to here. As the breeze of spring kisses the new greening grass, farmers begin tilling the soil and sowing barley seeds. These spiritual birds of the plateau, as if hearing a calling from the North, begin their mass migration. Seeing the silhouette of them flying further and further away, we cannot help but ask where they are heading.
Modern science and technology satisfied our quest for knowledge, even fulfilling our dreams. The latest developments in satellite-tracking techniques enable us to follow the birds’ migration. To understand the Black-necked Crane’s migration, a four-way partnership was organized, with the China Exploration & Research Society, Academia Sinica’s Kunming Institute of Zoology, the International Crane Foundation, and China’s National Bird Banding Center. In January 2009, after acquiring permission from the National Forestry Bureau to capture the cranes, the project was formally launched.
Freezing blizzards torched the landscape of Napahai during this coldest month of January. Even the thick-skinned furry yaks preferred to stay indoors in their barn. Our crane-capturing team left the CERS Center and was on its way at the first glimpse of dawn as the Land Rover bumped along the dirt road. Our approach scared into flight flocks of roosting ducks along the edge of the wetlands. But our team members were all excited and energetic, with eyesight trained on a group of Black-necked Cranes in front of us. Today, we must have a great field day, everyone thought.
Once we arrived at the site, CERS staff Ah So took on the forward charge, using an axe to crack the ice to make a safe path of approach. The rest of us followed with all the traps and various paraphernalia necessary to get the job done. The most important part of capturing the crane was to set the traps at a location they are likely to walk past. All efforts can be wasted if the traps are set at the wrong place. So planning by experts who know well the activity pattern of the cranes is crucial. The rest of the team would then place the traps according to plan. After four hours of strenuous labor in freezing cold and mud, the first batch of traps was successfully set. What remained was a protracted waiting game.
At the outset, we had mentally prepared ourselves for this difficult task. But it turned out the difficulties far surpassed our wildest imagination. In all, over a two-month period, we set more than 3,000 traps – but our capture record was dismal. There were over 40,000 other wintering birds at Napahai, a huge number compared to the 300 or so cranes which were our target. These migrating birds as well as other domestic animals created unexpected obstacles.
Unintentionally, we captured many ducks, Bar-headed Geese and Black Storks. Even pigs and a dog were caught in our traps. Despite being upset that these preys had messed up our traps, we had to quickly release them as we saw them looking at us with eyes of fright, begging for mercy. To ensure trapped cranes would not be injured, we had to check our traps twice a day, both in the morning and evening. Every time, we went out with high expectations, and each time, returned feeling disappointed and defeated. Morale and spirit gradually dissipated as we failed time after time in our effort to catch our first crane.
I was the person in charge of and responsible for this capturing and satellite tracking effort. That our efforts might fail weighed heavily on my mind. Failing to capture the cranes would mean aborting our project, our hard work wasted. I began to loose sleep and lost my appetite for food. Within a few weeks, what was weighing heavy in my mind translated into lightness in my body as I lost three kilograms.
There is an old saying in Chinese, “Three stupid leathersmiths can be smarter than one Ju Geliang” (Ju is considered one of the wisest among ancient Chinese scholars/military strategists). It means good team work can conquer the worst adversities. Thus I called a group meeting and tried to devise a new plan of action. We decided to change tactics by using a different type of trap and relocating them from the cranes’ feeding ground to the cranes’ roosting ground at night. Once this plan was agreed, everyone set to work and relocated all our new traps.
After over a month of trial and failures, on February 12, we finally caught our first adult crane. When I saw the captured crane in my spotting scope, tears came to my eyes. Everyone was so excited, it was beyond words. We rushed to the scene and rescued the crane from our trap. We quickly took all types of measurements of its physiology as well as other vital data. Then we carefully attached satellite tracking device Number 79631 onto the crane’s back.
The device is a tiny plastic box measuring barely 6.4 cm x 3.4 x 2.8 cm and weighing 88.7 grams, placing no restrictions on the bird’s normal flying or on-the-ground activities. There is a short antenna sticking up from the device as a transmitter to space- borne satellites orbiting high above. It is supposed to provide up to two years’ operation, allowing the bird’s daily location to be transmitted through satellite to ground stations and finally to our computer. Tracking data flows in continuously at six-hour intervals. Every night such data would be passed to me at 11 pm through email for analysis. When the device’s battery fails in about two year’s time, it will disengage itself and fall off the bird.
Once we switched on the device and released the crane, our computer would from now on track the bird’s whereabouts, allowing us to understand its daily activities. We watched this very fine adult crane walk off slightly unsteadily, before flying off into the distance. All of us could finally breathe an air of relief once it was out of sight. In our hearts, we prayed that it would continue to live happily and join the migration to a distant land for breeding.
Now our focus is no longer on catching cranes, but following the bird’s daily routine through satellite tracking. Where is it today at this specific time? Is it still healthy and unaffected by the frightful ordeal of being captured and handled? Has it left Napahai? Would it arrive safely at its migration destination for breeding? All these and other questions continued to nag us. Every night at 11 pm, I sat in front of my computer and waited anxiously for the new data to come in. Then the next morning, I would reveal the new location to our team.
On April 7 at around noon, Crane 79631 finally took flight and departed Napahai. On the third day after its departure, it arrived at a small alpine lake and wetland between Xinlong and Baiyu counties of western Sichuan. In all, it has flown over 400 kilometers spanning its wintering and summering grounds. Since arriving at this site, it has stayed put with a short range of daily activities. Black-necked Crane my friend, let us hope that we will meet again this coming winter at Napahai.
(A second crane was caught on March 14, a sub-adult which stayed at Napahai wintering site until late May. By chance or karma, the first crane stopped at its breeding site within a short distance of Tumu Monastery in northwestern Sichuan. This is where for many years CERS has been conducting landslide control in order to protect an important monastery.)